Method and apparatus for operating power motors with fuel gases of low boiling point



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llilvllflvlllllilllrld Filed NOV. 14, 1936 GASES OF LOW BOILING POINT METHOD AND APPARATUS FOR'OPERATING POWER MOTORS E. BRAuER 2,265,110 R OPERATING POWER MOTORS WITH FUEL POINT Dec. 2, 1941.

METHOD AND AP?ARATUS FO 1936 2 Sheets-Sheet 2 GASES 0F LOW BOILING Filed Nov. 14

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Illllll Patented 1941 UNITED STATES METHOD AN D ArrAnA'rUs FOR OPERATING POWER MOTORS WITH FUEL GASES OF LOW BOILING POINT Ernst Brii-uenvcigtsdorf, Germany ApplicationINovember 14, 1936, Serial No. 110,937

3' Claims.

This invention-relates to the use of fuel gases of low boiling point as fuel for engines. More particularly it has reference apparatus for conditioning fuel in the application of a method of this invention.

, The invention contemplates the use of fuelshaving low boiling points such as hydrogen, carbon monoxide, methane, and mixtures of such gases. In the following description the terms gas and fuel are intended to include any suitable fuels having a low boiling point and any suitable mixtures of such fuels But the invention is primarily directed'to gaseous fuel of a been fed with gases of low boiling point, i. e.

with hydrogen, carbon monoxide, methane and so forth, and possibly with mixtures of such gases; and such gases in a liquid condition, while they were kept ready for use. In so far as I am aware, it has not been possible hitherto to retain these fuels in liquid condition, while the engine associated with the fuel tank has been idle, since the 'unavoidable leakage of heat into the, container tends to develop dangerous pressures therein. I

This invention renders it possible to feed internal combustion engines with the said gases from a supply kept in liquid or solid condition, withoutallowing a dangerous rise of the pressure of the fuel supply in-general. More particularly no substantial rise over atmospheric pressure is to be permitted during the normal pauses in operation. Furthermore the normal working pressure of the tank is kept substantially lower than that of the atmosphere, preferably below the vapor tension of the contents at their In this case a further lowering of the pressure by evacuation of gas will effect vaporization, and the consumption of heat 'due to vaporization finally lowers the. temperature of the contents of the tank This invention also makes provisions for difboiling point.

' ficulties experienced in the past with fuel storage of the kind here discussed during thepauses in operation which accompany the use of certain engines, so that a new possibility arises for operating engines on the Diesel principle with liquefied gases of the type mentioned.

One embodiment of the invention is as fol- 4 to means for and to r a method of storing the gas and of supplying it to the motor. The invention further relates to so far that they solidify.

Germany April 5, 1933 lows: The fuel is transported, in the lowest pos-' sible subcooled liquid condition and stored in the same condition in large containers which are well insulated as regards heat. In certain cases the temperature may be lowered again by the withdrawale. g. pumping off-of gas. The withdrawn gas may be used in any desired manner, e. g. in heaters, furnaces, engines, or the like, it may be pressed into the network of a fuel gas supply system or it may be reliquefled.

Vehicles operating on land, air craft or water craft withdraw fuel from a storage tank into their heat insulated tanks. In spite of a heat increase the pressure in the vehicular tanks generally remains less than one atmosphere. The vehicular engines withdraw gas from the tanks, e. g. by means of the'piston movement itself or by means of a gas pump. The temperature of the contents of the tank is caused to drop by the tension at which the fuel solidifies. In the latter case the contents of the tank are thus rendered solid. In normal oper'ation, therefore, the application of a pre-compression of the fuel gas is necessary, 1. e. a raising of its pressure to the charging pressure of the engine.

Heat may be supplied by a removal of a part of the heat insulation of the tank. Heating may also be affected, by electricity, by the engine exhaust or the like. 'According to this invention heat may be supplied by leading the fuel gas through the tank by means of a conduit after the gas has been compressed. 'This offers the advantage that no condensation of moisture or carbonic acid or the like can take place at the heating surfaces. It is not objectionable if the compressed gas condenses again in the said heating conduit. There is no danger that said gas solidifies, because it is at a much higher pressure.

In a preferred embodiment of the invention ,the supply of heat is automatically cut in and out off. This may for instance be effected by an electro-magnetic device which is manometrically controlled and removes and replaces a section of the heat insulation of the tank, controls an electric heating current, or operates a cock in an exhaust gas conduit ,or in the said conduit for the compressed fuel gas.

Apparatus by which'a method of this invention may be put into practice is illustrated diagramevaporation. During continuation of the operamatically in the accompanying drawings, in

. which:

' externally,

engine, and

Each of the schematic, partly cross-sectioned views of Figs. 1, 2 and 3 illustrates a modification of the invention. -i

By way of a schematic top view and of a crosssectioned elevation Fig; 4 and Fig. 5 show details of the general arrangement for adaption of the invention to internal combustion engines.

Similarnumerals refer to similar parts throughout the various views:

In Fig. 1 the tank I5 is provided with a jacket Is for heat insulation and a pressure gauge II. A suction pump withdraws fuel from tank l5 and supplies it to an engine 8. A safety valve I9 is included in the system.

Insulation of the tank may be effected by evacuating the jacket Hi.

In the embodiment of Figs. 4 and 5 the fuel gas is supplied to an=internal combustion engine at a low, uniform pressure which is maintained by the reducing valve 3! even when the pressure in the tank has'been raised by heating. The engine is provided with two separate intakes 1 and 9 for fuel gas and by valves l and 2, respectively. A valve 3 is provided for the exhaust passage 53. A cam shaft are and cams 4, 5 and 6 control the valves and arranged so that at the beginning of the charging stroke, pure fuel gas at low pressureis sucked in until the cylinder contains the necessary amount of fuel gas. The air supply is then released and raises the pressure in the cylinder roughly to atmospheric pressure. A good mixing of fuel gas and air for combustion may be obtained by suitable means, preferably by suitable formation of the inlet channel.

It is not necessary, that the suction means, e. g. pump 20, exclusively performs the work necessary for removing from the storage In ans, e. g. tank Q5, all fuel required for the operation of an internal combustion engine. .By merely. warming up. the tank or part thereof, fuel contained therein is raised to a pressure above that of the atmos phere, so that it flows under its own pressure to the internal combustion engine. But such a process can only be of practical usefulness, when atthe same time a substantial proportion of the contents of the tank are retained at such a low temperature or pressure, that the said pro-' portion is capable of sufficiently cooling the warmed part of the contents ofthe tank and of reducing them to a pressure which does not involve any danger, after the internal combustion engine has been stopped and does not require any more fuel. 'This'isillustrated by the first embodiment shown-in Fig. 22' The tank is subair, which are controlled ment, which s to be heated. The heating of the withdrawn fuel takes place, for instance, in the container 35, which has a surface sufliciently large to allow the passage of the desired amount of heat from the environments into the container 35. When cock 3! is closed and cock 58' i opened, the fuel withdrawn by the pump 20 and warmed up' in container passes through the heating unit 36 depending into the compartment 33 of the tank and heats the contents of this compartment 33, so that their pressure rises above that of the atmosphere and they will flow in sufficient quantity to-the internal combustion engine 8, either directly or by way of the pump. The return tube of the heating unit 36 descends to a point near the bottom thereof, so that gas arriving from container 35 is guided up around said tube in heat transfer relationship with the outer wall of the depending heating unit 36 be-.

fore it'returns to engine 8. Similar heating units having analogous connections are provided in the divided into several part tanks or sectional compartment 32, 33, 34, which are well insulated to each other. In most of the compartments the and in certain cases also in respect' as is in a subcooled fluid or solid condition. The

compartment, however, from which the withdrawal takes place is heated to such a deg-rec.

that the pressure is above atmospheric pressure and the gas flows over to the internal combustion that the pump is subjected to a substantial load only at the beginning of the operation. partments, from which the fuel vis'to be withdrawn, is effected in the example illustrated in the drawings by the withdrawn fuel, after such withdrawn fuel has absorbed heat, thewithdrawn and heated fuel being circulated by means of a suitable conduit throughor around the compart- The heating of the one of the coin- 40 all valves and cocks are drawn by pump 20 from the'tanks and passes other compartments 32. and 34 which are assembled with compartment 33 in a common insulating enclosure.

During pauses or intervals between successive operations of the engine the pressure in the compartments might'rise more than permissible. As

a safeguard the admission of heat may suitably be checked, as forinstance illustrated in the arrangement of Fig. 2. Therethe supply of. heat ceases of itself in the stoppage of the-operation, since gas no longer flows to the internal combustion engine 8. Nevertheless the vapor space of the compartment 33 should be placed into communication-with the other compartments 32, 34 on each interruption of operations or in case the highest permissible pressure is exceeded. Then a portion of gas overflows from the last used compartment 33 into the other compartments and there it is condensed. The opening of cock 31 and of the connecting cocks 38, 39, 40 between the compartments can be effected automatically by the pressure in the compartments, for example by manometrically controlled switches in' the circuits of electro-magnets which turn the cocks. Such control means may be of any known form and as no claim is made to these means per se, they have not been illustrated.

following and valves are closed: Fuel feeds directly from tanks 32, 33 and 34 to engine 8. (2) With the exception of cock 31, 38, 39 and closed: Fuel is withthrough container 35 to engine 8.

(3) With the exception of cocks 31 and 60 all valves and cocks are open: Fuel isewithdrawn by pump 20 from the tanks and passes by way of container 35 and cock 59 through preheating units 36; and then through cocks 58 to engine 8.

A fourth modification of the invention is illustrated by Fig. 3, as follows: The tank is preferably subdivided into compartments in the manher just explained with Fig. 2. Of these only the compartment 4| is illustrated. To this compartment heat is supplied, for instance, by the electric heating coil 42, in the amount necessary to convert its solid contents into the liquid state. The fuel is withdrawn in this liquid condition. The pump I 3 pumps gas out of the gas'chamber of the compartment 4|, and forces it into the container 44. An electromotor 45 turns the control cocks 46-and 41 by mean of a worm and worm wheel 52, so that gas enters upon the dip space 48 alternately at a higher and a lower pressure. By means of the lift valves 49 and 50, this space acts as a liquid pump and delivers liquid fuel to the engine When the cock 46 is closed and the cock is open, the dip space 48 is connected with the suction side of the pump l3. The contents of the compartment 4| then-flow through the valve 50 into the space 48; When, conversely, the cock 46 is opened and the cock 4'! closed, the dip space 48 is connected with the pressure side of the pump [3 and the content of the space 48 are forced through the valve 49 into the pipe of the engine 5|. Of course another type of pump may be used in order to deliver the liquid from the tank 4|.

The fuel is either vaporized outside of the tank before being supplied to the engine, or it is burnt in a solid injection type engine.

I claim:

1. Method of providing normally gaseous fuel for the operation of an'int'ernal combustion engine comprising insulatedly storingfa sup ly of the gas in a non-gaseous state under partial vacuum by sub-cooling, applying heat to said supply during and for operation of the engine in order to drive of! the fuel required for such operation, and establishing after such operation communication of said supply with another similar supply which is under partial vacuum in a sub-cooled state, so that a partial vacuum is restored in said first supply.

2. A tank for storing sub-cooled normally gaseous fuel in a non-gaseous state in combination with an internal combustion engine in which the fuel is to be used, comprising compartments combined in said tank and heat-insulated outwardly and relatively to each other, and a pipe system by which each of said compartments may be connected separately to said engine for operation of the engine and by which the contents of the compartments are placed into exchange relationship with each other when the engine is not in operation.

3. A tank for storing sub-cooled normally gaseous fuel in a non-gaseous state in combination with an internal combustion engine in which the fuel is to be used, comprising compartments combined in said tank and heat-insulated outwardly and relatively to each other, heating means separately applicable to each of said compartments, and a pipe system by which a heated compartment may be connected separately to said engine for operation of the engine and by which the content of the compartments are placed into exchange relationship with each other when the engine is not in operation.

ERNST BRKUER. 

